1. Technical Field
This disclosure relates to a camera, and more specifically, to thermal compensation in integrated image sensor and lens assemblies.
2. Description of the Related Art
Manufacturing of lens assemblies for high-resolution cameras typically require a high degree of precision in positioning components of the lens assembly to ensure that the lens will achieve proper focus. As a result, a challenge exists in achieving a fast, automated, and high-yielding assembly process for high-resolution cameras.
In an integrated image sensor and camera lens system, a lens is coupled to an image sensor. A camera lens includes one or more lens elements. A camera lens can be coupled to the image sensor with a single-piece integrated mount or an assembly of at least a barrel holding the lens elements and a mount positioning the barrel with respect to the image sensor such that the image sensor is properly aligned with the lens to maintain image quality. For example, in a “permafocus” design, the camera lens is rigidly coupled to the image sensor after some alignment procedure.
The integrated system is susceptible to changes induced by environment. For example, camera lenses tend to defocus due to a temperature change. The defocus is a result of several factors, including thermal expansion of the lens elements, change in index of refraction of the lens elements, and thermal expansion of the barrel/mount and other components of the assembly. Thermal expansion is a function of the temperature change and the coefficient of thermal expansion (CTE) of the material.